Kingdom Hearts II Kingdom Hearts 2: Final Mix "Secret Rooms" help

I had Posted a previous thread in the Code Vault but was told to post here in the KH2KM topic area and not the code vault area.

I am confused on how to add the "secret rooms" such as Roxas' room on KH2FM, I have searched for tutorials but came across only one that was not well written and to confusing to be done properly. I am hoping that someone can tell me where to find a well written or send me a tutorial on how to get to these rooms. I use Code Breaker and I have the master code for KH2FM. Your help is greatly appreciated.

 

Do you mean adding the optional battles in that one room of TWTNW?

I think you have to beat the nobody bosses once to unlock each individual battle.

 

I am asking for the Code Breaker codes to access rooms that you cannot normally access in normal gameplay, sorry for not being specific before. Watch this video and youll see waht i mean:

http://www.youtube.com/watch?v=tVQVjgyDWDg&feature=related